"I come from a culture where you're not supposed to talk about yourself, you're never supposed to be impressed with yourself," says O'Brien, 45. "When I go home to Brookline, Mass., my parents still tell me to shut up and empty the dishwasher. That's the culture I come from."

But O'Brien also comes from a TV culture. He wrote for Saturday Night Live and The Simpsons. He replaced David Letterman at Late Night in 1993, drew mostly withering initial reviews, grew as a performer and lasted 16 years. He's leaving Late Night to take over The Tonight Show from Jay Leno in June.

Make no mistake: O'Brien wants to host The Tonight Show.

"I think there's something magical to me about NBC at 11:30," he says. "That's just a magic time. It was with Steve Allen and Jack Paar and Johnny Carson and Jay Leno. I intend to keep it that way."

And isn't The Tonight Show a promotion?

"It could be a demotion, and I haven't figured it out yet. Ask me in five years," O'Brien says, chuckling.

Everything fans like about the 12:30 Late Night will be in the 11:30 Tonight Show, O'Brien says, along with adjustments as he re-invents the show.

"It's got to be my version of The Tonight Show," O'Brien says. "It should be different from what Jay did, from what Johnny did. It's got to be unique. That's the only way it will work."

O'Brien notes that he auditioned for Late Night at 29.

"I think it is time for somebody younger to take over that show," O'Brien says. "I've done so many, weird strange things at 12:30 that I still can't believe I did. But I think it's time to move on." He adds that he's glad Jimmy Fallon will replace him.

O'Brien's stint at Late Night is remarkable because he received such negative reviews 16 years ago.

"Most people were just horrified," he says. "Who is this guy, and why is he replacing David Letterman? He looks 11 years old, and his voice hasn't changed."

Even so, O'Brien says he was proud of the early days and flying the freak flag early.

"I think the philosophy of the show was there on Day One, the spirit was there on Day One, but I had a lot to learn," he says. "I wasn't as confident back then. I had a lot to learn as a performer."

O'Brien has a plan for saying goodbye to Late Night. "We'd like a few special people to stop by," he says. "We're going to show a lot of clips toward the end that we're proudest of." Via the show's Web site, fans have a specific idea about what they want to see one more time, he added.

He describes the departure as tricky. "I don't want to look like I'm patting myself on the back," he says. "And also, I'm not leaving television forever. I'm going away for three months, then coming back."

He jokes that he'll have a lot of plastic surgery in the three months, but his distinctive hair won't need work.

"This isn't real," he says of his swooped-up do. "It comes off. I have 50 of these for every occasion. I had an operation about two years ago where they implanted a Velcro strip in the top of my head."

He says he owes his success to his hair. "Most of the studies that we've done show that people find me very distasteful," O'Brien says. "But the hair is so fascinating to them that they'll stick with the show."

In the competitive world of late night, the hair could make a difference.